The present invention relates to silicone polyimides which are substantially insoluble in chlorinated organic solvents and which are useful as melt extrudable wire coating compositions.
Prior to the present invention, as shown by Rich et al, U.S. Pat. No. 4,795,680, incorporated herein by reference and assigned to the same assignee as the present invention, polyimide siloxanes were provided resulting from the condensation of organic diamines and organosiloxanes having terminal silyl substituted aromatic organic anhydride groups. For example, there are included by the polyimide siloxanes of Rich et al, silicone polyimides resulting from the reaction of organic diamines and aromatic anhydride terminated organopolysiloxanes of the formula, ##STR1## hereinafter referred to as "PADS", where R is a C.sub.(1-14) monovalent hydrocarbon radical, or a C.sub.(1-14) monovalent hydrocarbon radical substituted with the same or different radicals inert during intercondensation, R.sup.1 is a C.sub.(6-14) trivalent aromatic organic radical, and n is an integer equal to 1 to about 2000 inclusive.
Although silicone polyimides made from PADS of U.S. Pat. No. 4,795,680 are useful as insulation for electrical conductors, coatings and numerous other applications, flame retardant wire coating compositions having improved solvent resistance are constantly being evaluated by manufacturers of wire coating materials.